Nanosized Si3N4/SiC-powders by polysilazane/polycarbosilane-pyrolysis
Abstract
The preparation of the nanosized powders has been realized by gasphase-pyrolysis of volatile precursor compounds at temperatures between 600 and 1200 °C. Silicon carbonitride powders have been created from polysilazanes, which have been synthesized by ammonolysis of alkylchlorosilanes. Silicon carbide powders have been prepared from 1,1,3,3-tetramethyl-1,3-disilacyclobutane, gained by the dechlorination- and coupling reaction of chloromethyldimethylchlorosilane with magnesium. The ball-like powder particles have a diameter between 100 and 500 nm and a surface of 10 to 50 m2/g. They are X-ray amorphous and can be crystallized upper 1400 °C to a-Si3N4 and v-SiC respectively.
